title: Life cycle assessment of energy from waste via anaerobic digestion: a UK case study.
abstract: Particularly in the UK, there is potential for use of large-scale anaerobic digestion (AD) plants to treat food waste, possibly along with other organic wastes, to produce biogas. This paper presents the results of a life cycle assessment to compare the environmental impacts of AD with energy and organic fertiliser production against two alternative approaches: incineration with energy production by CHP and landfill with electricity production. In particular the paper investigates the dependency of the results on some specific assumptions and key process parameters. The input Life Cycle Inventory data are specific to the Greater London area, UK. Anaerobic digestion emerges as the best treatment option in terms of total CO2 and total SO2 saved, when energy and organic fertiliser substitute non-renewable electricity, heat and inorganic fertiliser. For photochemical ozone and nutrient enrichment potentials, AD is the second option while incineration is shown to be the most environmentally friendly solution. The robustness of the model is investigated with a sensitivity analysis. The most critical assumption concerns the quantity and quality of the energy substituted by the biogas production. Two key issues affect the development and deployment of future anaerobic digestion plants: maximising the electricity produced by the CHP unit fuelled by biogas and to defining the future energy scenario in which the plant will be embedded.
authors.affiliation: Chemical Engineering Department, University College London, Torrington Place, London WC1E 7JE, UK; Dipartimento di Ingegneria Meccanica e Aerospaziale, Sapienza Università di Roma, via Eudossiana 8, 00184 Roma, Italy. Electronic address: sara.evangelisti.11@ucl.ac.uk.
authors.forename: Sara
authors.initials: S
authors.lastname: Evangelisti
authors.forename: Paola
authors.initials: P
authors.lastname: Lettieri
authors.forename: Domenico
authors.initials: D
authors.lastname: Borello
authors.forename: Roland
authors.initials: R
authors.lastname: Clift
mesh_terms: D000693:Anaerobiosis; D056804:Biofuels; D004736:Energy-Generating Resources; D017745:Incineration / Q000379:methods; D008962:Models, Theoretical; D012037:Refuse Disposal / Q000379:methods*; D006113:United Kingdom; D064091:Waste Disposal Facilities; D014866:Waste Products / Q000032:analysis
chemical_list: D056804:Biofuels; D014866:Waste Products
keywords: Anaerobic digestion; Digestate use; Life cycle assessment; Organic waste; Sensitivity analysis; System expansion